Yes; the EGKA one is to stop you hitting the train when landing on 02.
Other reasons are to reduce noise seen by houses which were built too close to the runway start.
Peter wrote:
Yes; the EGKA one is to stop you hitting the train when landing on 02.
Peter, that is if you follow the designated approach angle, right? You can avoid obstacles and produce less noise while landing before the threshold if you follow steeper glideslope.
Sure.
As to legality, I don’t know. It is probably one of those airport rule things where if you repeatedly break it you might get kicked off the airport.
Peter wrote:
It is probably one of those airport rule things where if you repeatedly break it you might get kicked off the airport.
Cambridge got the following in it’s AIP:
Aircraft approaching asphalt Runway 05/23 without assistance from Radar (or ILS, Runway 23) shall follow a descent path from at least 1000 FT that is no lower than the normal approach path indicated by the PAPI. Which means you should touchdown way down the runway!
@Graham, from CAP168:
Landing Distance Available (LDA) The distance from the point on the surface of the
aerodrome above which the aeroplane can commence its landing, having regard to the
obstructions in its approach path, to the nearest point in the direction of landing at which
the surface of the aerodrome is incapable of bearing the weight of the aeroplane under
normal operating conditions or at which there is an obstacle capable of affecting the safety
of the aeroplane.
That definition is taken out of context. Though It is not incompatible with the definition graham provided. It is can be applied to water as well as open fields for example, or to a runway.
If you look further in that document when it’s referring to real runways the definition is exactly as graham gave
I.e
3.202
4. LDA. This is the length of runway available and suitable for the ground landing run of an aeroplane
Hm. Somehow in my brain it was ingrained that LDA is Landing Distance Available, which means from 50ft above the runway. @Airborne_Again, what does ICAO say here?
Graham wrote:
I’m asking the question genuinely here, because I didn’t think landing before the displaced threshold was permitted.
LDA is available horizontal distance of the runway declared available by the competent authority. The displaced threshold is not part of it. Thus, I agree with your thinking. Landing before the threshold is not permissible.
My training was to land past the displaced threshold, because that way the aircraft noise under the final approach path is a bit less. If it doesn’t work out, you’re still on the runway but should learn to do it better next time. I was not instructed that landing slightly short of the designated spot on the runway is illegal and subject to possible prosecution. That’s just absurd.
In my plane I typically do approaches that are much steeper than 3 degrees, descending onto the PAPI on half mile final, so it wouldn’t make any difference either way. Also my plane does not exactly roar when the throttle is closed.
arj1 wrote:
Somehow in my brain it was ingrained that LDA is Landing Distance Available, which means from 50ft above the runway. @Airborne_Again, what does ICAO say here?
In Annex 14, ICAO says that the LDA is “The length of runway which is declared available for the ground run of an aeroplane landing.” It also makes clear that the LDA is the distance from the threshold to the far end of the runway. (So any displaced threshold at the far end is disregarded, as are any stopway or clearway at the far end.)
Another thing is that the threshold location depends on the obstacle situation, but that is determined much more conservatively than for a 3° glidepath passing the threshold at 50 ft. The obstacle clearance slope is much flatter and ends well in front of the threshold. (The exact figures depend on the runway code.)
LDA is clearly defined in the EU regulation 2020/469 as: „The length of the RWY, declared available and suitable for the ground run of an aeroplane landing.“ – means, everything including the displaced threshold is not suitable for a landing. What that means or might result in differs from country to country. In Germany, it’s definitely an off airport landing – and that what also usually instructors teach you.
